Drug Interaction Report

MONITOR: Concomitant use of avatrombopag with strong CYP450 3A4/5 or CYP450 2C9 inducers may decrease the systemic exposure (AUC) of avatrombopag which may lead to reduced efficacy.

MANAGEMENT: No dose adjustment is recommended; however, it may be advisable to monitor platelet count for signs of decreased efficacy of avatrombopag.

ADJUST DOSING INTERVAL: Fat-rich food enhances the absorption of mitotane. One study evaluated blood levels of mitotane (o,p'-DDD) after subjects ingested a single dose of 2 g administered using various delivery vehicles (e.g., tablets, granules, milk, chocolate or oil emulsion). Mitotane plasma levels were significantly higher for milk, chocolate, and oil emulsion when compared to those who received tablets or granules alone. In the same study, mitotane levels were evaluated in subjects following long-term treatment (total dose of 200 g over 30 to 60 days) in tablet, oil emulsion, or milk formulations. Significantly higher mean plasma levels were recorded in subjects who received mitotane as an oil emulsion or mixed in milk, when compared to tablets alone. Additionally, the recovery of o,p'-DDD from the feces was about 5 times higher in subjects who received tablets alone, suggesting absorption was reduced when compared to subjects who received mitotane mixed with a fat-rich vehicle (e.g., oil emulsion or milk).

GENERALLY AVOID: Concomitant use of mitotane with central nervous system (CNS) depressants, including alcohol, may potentiate adverse effects such as somnolence and sedation.

MANAGEMENT: According to product labeling, mitotane tablets should be taken during meals containing fat-rich food (e.g., milk, chocolate, or oil) and with a full glass of water. Patients should be advised to avoid or limit consumption of alcohol and to avoid activities requiring mental alertness such as driving or operating hazardous machinery until they know how the medication affects them.

ADJUST DOSING INTERVAL: Food reduces the variability in oral absorption and bioavailability of avatrombopag. According to the product labeling, avatrombopag peak plasma concentration (Cmax) and systemic exposure (AUC) were not affected when administered with either a low-fat (500 calories; 3 g fat, 15 g proteins, 108 g carbohydrates) or high-fat (918 calories; 59 g fat, 39 g proteins, 59 g carbohydrates) meal. However, the variability of avatrombopag exposure was reduced by 40% to 60% with food, and the time to reach Cmax was delayed by 0 to 2 hours relative to the fasted state.

MANAGEMENT: To ensure consistent absorption and plasma drug levels, avatrombopag should be taken with food.